AT&T filed a lawsuit on 19 October 2007 against VoIP provider Vonage Holdings, seeking damages for alleged patent infringement, just days after Vonage settled a patent infringement lawsuit with telecom provider Sprint Nextel Corp.
AT&T alleges that Vonage wilfully infringed an AT&T patent related to telephone systems that allow people to make VoIP calls using standard telephone devices.
In the legal filing, AT&T stated that the lawsuit had been forced because it had tried and failed to reach an agreement with Vonage to license the patent.
On 8 October, Vonage settled its suit with Sprint Nextel for $80m. As part of that agreement, Vonage agreed to license VoIP patents from Sprint, including more than 100 patents covering technology for connecting calls from a traditional phone network to an IP network.
Vonage is also in the process of resolving a patent infringement dispute with Verizon Communications Inc. Earlier this year, a court found Vonage infringed on Verizon patents and ordered an injunction that could have prevented Vonage from signing up new customers.
Vonage won an injunction staying the order and is appealing against the original infringement ruling. In August 2007, Vonage announced that it was close to introducing solutions for two of the three patents Verizon claimed.
Vonage is one of the largest independent VoIP providers in the United States, with approximately 2.5 million customers.